1. Department of Medicine, Division of Gastroenterology and Hepatology, Esophageal and Swallowing Center, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, USA
2. Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University, Stanford, CA, USA
3. Department of Gastroenterology, ABC Medical Center PMG, Santa Fe, Contadero, Cuajimalpa de Morelos, Mexico
4. Deapartment of Digestive Physiology and Motility Laboratory, Medical Biological Research Institute, University of Veracruz, Veracruz, Mexico
5. Department of Medicine, Division of Gastroenterology and Hepatology, Digestive Disease Center, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA
6. Department of Medicine, Division of Gastroenterology and Hepatology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH, USA